This invention relates to crop gathering attachments for crop harvesting machines.
It is usual in crop harvesting machines for standing crop to be harvested by first cutting it and then feeding the cut crop to crop processing components such as a threshing and separating mechanism in the case of a combine harvester, or a chopper in the case of a forage harvester, for example. The feeding of the cut crop to the crop processing components needs to be fluent and consistent so as to load those components uniformly and hence maximize the capacity of the machine. In some known machines the means, such as an auger, for feeding the cut crop to the crop processing means are located at a relatively short distance behind the cutter means which is desirable from the standpoint of positively moving the crop to the processing means immediately after it has been cut but which gives rise to the problem, in some instances, of crop being acted upon by the feeder means before it is cut and thus being pulled. This tends to happen with crop having long stalks (such as rye and rape for example) which is not standing upright due to adverse weather conditions.
Another problem experienced with known machines arises when the crop is wet and/or infested with weeds. With crop in either of these conditions there is a problem of achieving a fluent flow and there is a tendency for crop to accumulate in the dead spot which inevitably exists between the cutter means and feeder means even if a reel is used to help sweep the crop first to the cutter means and thence to the feeder means.
There exists a device which is employed between the cutter means and the feeder means and which in effect constitutes additional feeder means. The device in question is the so-called draper and a crop gathering attachment embodying the same is disclosed in U.S. Pat. No. 4,038,809. Since the draper separates the cutter and the normal feeder means and is itself not as aggressive as the latter, then the aforementioned problem of pulling long-stalked crops before they are cut is avoided. Also, the problem associated with the dead spot in which wet or weed-infested crop tends to accumulate is relieved.
However, the draper is in effect a continuous belt conveyor, usually made of convas, and it is difficult to provide adequate tracking means without using complicated, and hence expensive, components for the belt. Also, crop material tends to wrap around the ends of the shafts carrying the canvas belt and eventually gets between the belt and the shafts. This, together with inadequate tracking, results in belt replacement. For this reason, the draper has not become a universally accepted device.